Add checkreturnvalue

Author: vlsi

core/src/main/java/org/apache/calcite/plan/RelTraitSet.java

@@ -33,6 +33,7 @@
 import java.util.List;
 import java.util.Map;
 import java.util.function.Supplier;
+import javax.annotation.CheckReturnValue;
 
 /**
  * RelTraitSet represents an ordered set of {@link RelTrait}s.
@@ -73,6 +74,7 @@ private RelTraitSet(Cache cache, RelTrait[] traits) {
    * <p>It has a new cache, which will be shared by any trait set created from
    * it. Thus each empty trait set is the start of a new ancestral line.
    */
+  @CheckReturnValue
   public static RelTraitSet createEmpty() {
     return new RelTraitSet(new Cache(), EMPTY_TRAITS);
   }
@@ -125,6 +127,7 @@ public <T extends RelTrait> boolean isEnabled(RelTraitDef<T> traitDef) {
    * @param traitDef the type of RelTrait to retrieve
    * @return the RelTrait, or null if not found
    */
+  @CheckReturnValue
   public <T extends RelTrait> @Nullable T getTrait(RelTraitDef<T> traitDef) {
     int index = findIndex(traitDef);
     if (index >= 0) {
@@ -143,6 +146,7 @@ public <T extends RelTrait> boolean isEnabled(RelTraitDef<T> traitDef) {
    * @param traitDef the type of RelTrait to retrieve
    * @return the RelTrait, or null if not found
    */
+  @CheckReturnValue
   public <T extends RelMultipleTrait> @Nullable List<T> getTraits(
       RelTraitDef<T> traitDef) {
     int index = findIndex(traitDef);
@@ -162,6 +166,7 @@ public <T extends RelTrait> boolean isEnabled(RelTraitDef<T> traitDef) {
    * @param trait the new RelTrait
    * @return the old RelTrait at the index
    */
+  @CheckReturnValue
   public RelTraitSet replace(int index, RelTrait trait) {
     assert traits[index].getTraitDef() == trait.getTraitDef()
         : "RelTrait has different RelTraitDef than replacement";
@@ -185,6 +190,7 @@ public RelTraitSet replace(int index, RelTrait trait) {
    * @return New set
    * @see #plus(RelTrait)
    */
+  @CheckReturnValue
   public RelTraitSet replace(
       RelTrait trait) {
     // Quick check for common case
@@ -218,6 +224,7 @@ private static <T> boolean containsShallow(T[] ts, RelTrait seek) {
    *
    * <p>The list must not be empty, and all traits must be of the same type.
    */
+  @CheckReturnValue
   public <T extends RelMultipleTrait> RelTraitSet replace(List<T> traits) {
     assert !traits.isEmpty();
     final RelTraitDef def = traits.get(0).getTraitDef();
@@ -229,13 +236,15 @@ public <T extends RelMultipleTrait> RelTraitSet replace(List<T> traits) {
    *
    * <p>The list must not be empty, and all traits must be of the same type.
    */
+  @CheckReturnValue
   public <T extends RelMultipleTrait> RelTraitSet replace(RelTraitDef<T> def,
       List<T> traits) {
     return replace(RelCompositeTrait.of(def, traits));
   }
 
   /** If a given multiple trait is enabled, replaces it by calling the given
    * function. */
+  @CheckReturnValue
   public <T extends RelMultipleTrait> RelTraitSet replaceIfs(RelTraitDef<T> def,
       Supplier<List<T>> traitSupplier) {
     int index = findIndex(def);
@@ -247,6 +256,7 @@ public <T extends RelMultipleTrait> RelTraitSet replaceIfs(RelTraitDef<T> def,
   }
 
   /** If a given trait is enabled, replaces it by calling the given function. */
+  @CheckReturnValue
   public <T extends RelTrait> RelTraitSet replaceIf(RelTraitDef<T> def,
       Supplier<T> traitSupplier) {
     int index = findIndex(def);
@@ -263,6 +273,7 @@ public <T extends RelTrait> RelTraitSet replaceIf(RelTraitDef<T> def,
    * @param mapping   Mapping
    * @return traitSet with mapping applied
    */
+  @CheckReturnValue
   public RelTraitSet apply(Mappings.TargetMapping mapping) {
     RelTrait[] newTraits = new RelTrait[traits.length];
     for (int i = 0; i < traits.length; i++) {
@@ -402,6 +413,7 @@ public int size() {
    * @param trait Trait
    * @return Trait in canonical form
    */
+  @CheckReturnValue
   public <T extends RelTrait> T canonize(T trait) {
     if (trait == null) {
       // Return "trait" makes the input type to be the same as the output type,
@@ -621,6 +633,7 @@ private int findIndex(RelTraitDef traitDef) {
    * @param trait Trait
    * @return Trait set with given trait
    */
+  @CheckReturnValue
   public RelTraitSet plus(RelTrait trait) {
     if (contains(trait)) {
       return this;
@@ -637,6 +650,7 @@ public RelTraitSet plus(RelTrait trait) {
     return cache.getOrAdd(new RelTraitSet(cache, newTraits));
   }
 
+  @CheckReturnValue
   public RelTraitSet plusAll(RelTrait[] traits) {
     RelTraitSet t = this;
     for (RelTrait trait : traits) {
@@ -645,12 +659,14 @@ public RelTraitSet plusAll(RelTrait[] traits) {
     return t;
   }
 
+  @CheckReturnValue
   public RelTraitSet merge(RelTraitSet additionalTraits) {
     return plusAll(additionalTraits.traits);
   }
 
   /** Returns a list of traits that are in {@code traitSet} but not in this
    * RelTraitSet. */
+  @CheckReturnValue
   public ImmutableList<RelTrait> difference(RelTraitSet traitSet) {
     final ImmutableList.Builder<RelTrait> builder = ImmutableList.builder();
     final int n =
@@ -680,6 +696,7 @@ public boolean allSimple() {
 
   /** Returns a trait set similar to this one but with all composite traits
    * flattened. */
+  @CheckReturnValue
   public RelTraitSet simplify() {
     RelTraitSet x = this;
     for (int i = 0; i < traits.length; i++) {
@@ -701,6 +718,7 @@ private static class Cache {
     Cache() {
     }
 
+    @CheckReturnValue
     RelTraitSet getOrAdd(RelTraitSet t) {
       RelTraitSet exist = map.putIfAbsent(t, t);
       return exist == null ? t : exist;